YCbCr = rgb2YCbCr(I::GMTimage{UInt8, 3}; Y=false, Cb=false, Cr=false, BT709=false)
or
Y,Cb,Cr = rgb2YCbCr(I::GMTimage{UInt8, 3}; Y=false, Cb=false, Cr=false, BT709=false)Convert RGB color values to luminance (Y) and chrominance (Cb and Cr) values of a YCbCr image.
Optionally, return only one to three of Y, Cb and Cr in separate images. For that use the keywords: Y, Cb or Cr. Each true occurence makes it return that component, otherwise it returns an empty image. The alternative rgb2ycbcr alias (all lowercase) is also accepted.
I::GMTimage{UInt8, 3}: input RGB image.Y: If true return the luminance (Y) component.
Cb: If true return the Cb component.
Cr: If true return the Cr component.
BT709: If true use the ITU-R BT.709 conversion instead of the default ITU-R BT.601. See https://en.wikipedia.org/wiki/YCbCr
A RGB GMTimage or up to three GMTimages grayscales images with the luminance (Y), Cb and Cr components.
using GMT
# Read an RGB image
I = gmtread(GMT.TESTSDIR * "assets/seis_section_rgb.jpg");
Iycbcr = rgb2YCbCr(I);
# The Cb and Cr components
_,Cb,Cr = rgb2YCbCr(I, Cb=true, Cr=true);
# Show the four.
grdimage(I, figsize=6)
grdimage!(Iycbcr, figsize=6, yshift=-2.84)
grdimage!(Cb, figsize=6, yshift=-2.84)
grdimage!(Cr, figsize=6, yshift=-2.84, show=true)